Present day aircraft performing autonomous landings on naval vessels rely on a ship-mounted, radar-based landing system that is susceptible to component failures. Such a failure would require the aircraft to divert from the intended host platform to another radar-landing-system-equipped vessel or land-based facility. If an acceptably equipped alternate vessel or land facility is out of range or unavailable, a multi-million dollar asset would have to be ditched at sea.
Methods exist for measuring the relative altitude and attitude of an aircraft with respect to a surface. For example, U.S. Patent Application Publication Number 2012/0130566 to Anderson (“Anderson”) discusses a system for facilitating autonomous landing of aerial vehicles on a surface, comprising beam emitting means directed downwards and control means to govern the vehicle, wherein the system is characterized in that it comprises image capturing means and processing means to process image data, wherein the beam emitting means are arranged to emit simultaneously at least four beams directed towards the surface in order to project a pattern thereon, wherein one beam emitting means of the at least four beam emitting means is placed in the centre; and that the image capturing means captures subsequent images of the pattern.
Similarly, U.S. Patent Application Publication Number 2011/0307126 to Hogstrom (“Hogstrom”) discusses a system for predicting the movement of a surface for autonomous landing of unmanned aerial vehicles (UAVs), which comprises beam emitting means, control means, detector means to detect reflected beams, processing means to process measurements, and storing means to store the processed measurements, and which is characterized in that it comprises at least two beam emitting means, and in that each of the at least two beam emitting means is movable to measure along at least one line on the surface.
Other onboard landing systems rely on computer vision to interpret ship geometry from which the relative alignment of the aircraft can be deduced. For example, U.S. Patent Publication Number 2011/0307126 to Markiton, et al, which teaches a method and a device for assisting with flying an aircraft, which are intended to assist with flying the aircraft at least during an autonomous landing approach to a runway with a view to landing, particularly in the field of military aircraft. Similarly U.S. Patent Publication Number 2009/0306840 to Blenkhorn, et al teaches systems, methods, devices, and computer readable media for landing unmanned aerial vehicles using sensor input and image processing techniques. Finally U.S. Patent Publication Number 2010/0057278 to Lee teaches a system for automatically landing an aircraft using image signals, and, more particularly, to a system for automatically landing an aircraft using image signals and a method of controlling the system, which are capable of automatically landing an aircraft at a landing location using a landing mark provided at the landing location and imaging equipment configured to detect the landing mark.
Moreover, existing methods fail to address the complete problems of locating and approaching the ship from a distance, detecting the touchdown point and safely positioning the aircraft over the touchdown point, and tracking the touchdown point to touchdown. Finally, existing methods rely on ship-mounted, radar-based landing equipment which may provide unnecessary risks and limitations.